==================================================================
BUG: KASAN: use-after-free in link_path_walk+0x1375/0x1710 fs/namei.c:1949
Read of size 4 at addr ffff8800ba25af20 by task syz-executor0/26030

CPU: 1 PID: 26030 Comm: syz-executor0 Not tainted 4.4.131-gaa3863d #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 0000000000000000 0014208999caae9a ffff8801d2af7890 ffffffff81e0df8d
 ffffea0002e89680 ffff8800ba25af20 0000000000000000 ffff8800ba25af20
 ffff8801d2af7c70 ffff8801d2af78c8 ffffffff8151520c ffff8800ba25af20
Call Trace:
 [<ffffffff81e0df8d>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81e0df8d>] dump_stack+0xc1/0x124 lib/dump_stack.c:51
 [<ffffffff8151520c>] print_address_description+0x6c/0x216 mm/kasan/report.c:252
 [<ffffffff8151552b>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff8151552b>] kasan_report.cold.7+0x175/0x2f7 mm/kasan/report.c:408
 [<ffffffff814f9004>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff8154a355>] link_path_walk+0x1375/0x1710 fs/namei.c:1949
 [<ffffffff8154b624>] path_openat+0x1a4/0x3a10 fs/namei.c:3358
 [<ffffffff81551ba7>] do_filp_open+0x197/0x270 fs/namei.c:3393
 [<ffffffff8151b26c>] do_sys_open+0x31c/0x610 fs/open.c:1038
 [<ffffffff816267ad>] C_SYSC_openat fs/compat.c:1101 [inline]
 [<ffffffff816267ad>] compat_SyS_openat+0x2d/0x40 fs/compat.c:1099
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c17aa>] sysenter_flags_fixed+0xd/0x17

Allocated by task 26024:
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=13361 sclass=netlink_route_socket
 [<ffffffff810341d6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f80d3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f83b7>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f83b7>] kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:616
SELinux: unrecognized netlink message: protocol=0 nlmsg_type=13361 sclass=netlink_route_socket
 [<ffffffff814f8982>] kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:554
 [<ffffffff814f447e>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff814f447e>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff814f447e>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff814f447e>] kmem_cache_alloc+0xbe/0x2a0 mm/slub.c:2628
 [<ffffffff8156a07e>] __d_alloc+0x2e/0x7b0 fs/dcache.c:1589
 [<ffffffff8156aaa7>] d_make_root+0x47/0x90 fs/dcache.c:1934
 [<ffffffff8184196d>] ramfs_fill_super+0x35d/0x490 fs/ramfs/inode.c:232
 [<ffffffff815262cb>] mount_nodev+0x5b/0x100 fs/super.c:1086
 [<ffffffff81840e0c>] ramfs_mount+0x2c/0x40 fs/ramfs/inode.c:242
 [<ffffffff815282fc>] mount_fs+0x28c/0x370 fs/super.c:1146
 [<ffffffff81580091>] vfs_kern_mount.part.30+0xd1/0x3d0 fs/namespace.c:991
 [<ffffffff815876de>] vfs_kern_mount fs/namespace.c:973 [inline]
 [<ffffffff815876de>] do_new_mount fs/namespace.c:2517 [inline]
 [<ffffffff815876de>] do_mount+0x4ee/0x2860 fs/namespace.c:2833
 [<ffffffff8162566a>] C_SYSC_mount fs/compat.c:824 [inline]
 [<ffffffff8162566a>] compat_SyS_mount+0x57a/0x1040 fs/compat.c:789
 [<ffffffff81006d96>] do_syscall_32_irqs_on arch/x86/entry/common.c:392 [inline]
 [<ffffffff81006d96>] do_fast_syscall_32+0x326/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c17aa>] sysenter_flags_fixed+0xd/0x17

Freed by task 26024:
 [<ffffffff810341d6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff814f80d3>] save_stack+0x43/0xd0 mm/kasan/kasan.c:512
 [<ffffffff814f8a02>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff814f8a02>] kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:589
 [<ffffffff814f5b8e>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff814f5b8e>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff814f5b8e>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff814f5b8e>] kmem_cache_free+0xbe/0x340 mm/slub.c:2881
 [<ffffffff815617f5>] __d_free fs/dcache.c:257 [inline]
 [<ffffffff815617f5>] dentry_free+0xd5/0x150 fs/dcache.c:333
 [<ffffffff8156383c>] __dentry_kill+0x4ac/0x5f0 fs/dcache.c:576
 [<ffffffff81567117>] dentry_kill fs/dcache.c:603 [inline]
 [<ffffffff81567117>] dput.part.26+0x587/0x760 fs/dcache.c:818
 [<ffffffff81569163>] dput fs/dcache.c:782 [inline]
 [<ffffffff81569163>] do_one_tree+0x43/0x50 fs/dcache.c:1473
 [<ffffffff81569f82>] shrink_dcache_for_umount+0x62/0x130 fs/dcache.c:1487
 [<ffffffff8152391d>] generic_shutdown_super+0x6d/0x300 fs/super.c:413
 [<ffffffff815241a2>] kill_anon_super fs/super.c:914 [inline]
 [<ffffffff815241a2>] kill_litter_super+0x72/0x90 fs/super.c:924
 [<ffffffff81840dcf>] ramfs_kill_sb+0x3f/0x50 fs/ramfs/inode.c:248
 [<ffffffff8152467d>] deactivate_locked_super+0x8d/0xd0 fs/super.c:301
 [<ffffffff81524fc1>] deactivate_super+0x91/0xd0 fs/super.c:332
 [<ffffffff8157f342>] cleanup_mnt+0xb2/0x160 fs/namespace.c:1119
 [<ffffffff8157f476>] __cleanup_mnt+0x16/0x20 fs/namespace.c:1126
 [<ffffffff8118bb8f>] task_work_run+0x10f/0x190 kernel/task_work.c:115
 [<ffffffff8100362d>] tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 [<ffffffff8100362d>] exit_to_usermode_loop+0x13d/0x160 arch/x86/entry/common.c:252
 [<ffffffff81007090>] prepare_exit_to_usermode arch/x86/entry/common.c:283 [inline]
 [<ffffffff81007090>] syscall_return_slowpath arch/x86/entry/common.c:348 [inline]
 [<ffffffff81007090>] do_syscall_32_irqs_on arch/x86/entry/common.c:398 [inline]
 [<ffffffff81007090>] do_fast_syscall_32+0x620/0x8b0 arch/x86/entry/common.c:459
 [<ffffffff838c17aa>] sysenter_flags_fixed+0xd/0x17

The buggy address belongs to the object at ffff8800ba25af20
 which belongs to the cache dentry of size 288
The buggy address is located 0 bytes inside of
 288-byte region [ffff8800ba25af20, ffff8800ba25b040)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 26033 Comm: syz-executor3 Not tainted 4.4.131-gaa3863d #39
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8800b6930000 task.stack: ffff8801bcaf0000
RIP: 0010:[<ffffffff81e6fa81>]  [<ffffffff81e6fa81>] lookup_object lib/debugobjects.c:120 [inline]
RIP: 0010:[<ffffffff81e6fa81>]  [<ffffffff81e6fa81>] debug_object_deactivate+0x191/0x340 lib/debugobjects.c:465
RSP: 0000:ffff8801db207cf0  EFLAGS: 00010007
RAX: dffffc0000000000 RBX: 00000000f56ec0ac RCX: 000000001eadd818
RDX: 0000000000000000 RSI: ffffffff844c64e0 RDI: 00000000f56ec0c4
RBP: ffff8801db207da8 R08: ffffffff85331830 R09: 0000000000000001
R10: 0000000000000001 R11: ffff8800b6930000 R12: 1ffff1003b640fa0
R13: ffffffff85a32da8 R14: ffff8800bb2bfd28 R15: 000000000005fd9e
FS:  0000000000000000(0000) GS:ffff8801db200000(0063) knlGS:000000000852f900
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000f77eebe9 CR3: 00000001d4ba2000 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000092 ffffffff844c64e0 0000000041b58ab3 ffffffff84208e47
 ffffffff81e6f8f0 ffff8800b6930000 ffffed0016d2611b ffff8800b69308e0
 ffff8801db219658 0000000000000002 ffff8801db207d80 ffffffff81229462
Call Trace:
 <IRQ> 
 [<ffffffff8129d992>] debug_hrtimer_deactivate kernel/time/hrtimer.c:415 [inline]
 [<ffffffff8129d992>] debug_deactivate kernel/time/hrtimer.c:462 [inline]
 [<ffffffff8129d992>] __run_hrtimer kernel/time/hrtimer.c:1230 [inline]
 [<ffffffff8129d992>] __hrtimer_run_queues+0x222/0x1000 kernel/time/hrtimer.c:1325
 [<ffffffff8129f291>] hrtimer_interrupt+0x1b1/0x430 kernel/time/hrtimer.c:1359
 [<ffffffff810ad554>] local_apic_timer_interrupt+0x74/0xa0 arch/x86/kernel/apic/apic.c:901
 [<ffffffff838c2a8c>] smp_apic_timer_interrupt+0x7c/0xa0 arch/x86/kernel/apic/apic.c:925
 [<ffffffff838c19d0>] apic_timer_interrupt+0xa0/0xb0 arch/x86/entry/entry_64.S:741
 <EOI> 
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
 [<ffffffff8148c947>] dump_page mm/debug.c:105 [inline]
 [<ffffffff8148c947>] page_mapcount include/linux/mm.h:464 [inline]
 [<ffffffff8148c947>] dump_page_badflags+0x57/0x70 mm/debug.c:85
Code: a9 01 00 00 48 8b 1b 41 bf 01 00 00 00 48 85 db 74 42 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 18 41 83 c7 01 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f 85 0c 01 00 00 4c 3b 73 18 74 7d 48 89 d9 48 c1 
RIP  [<ffffffff81e6fa81>] lookup_object lib/debugobjects.c:120 [inline]
RIP  [<ffffffff81e6fa81>] debug_object_deactivate+0x191/0x340 lib/debugobjects.c:465
 RSP <ffff8801db207cf0>
---[ end trace 2478fbef37881af6 ]---